Track driven/tracked and wheeled vehicles of today are typically driven by drive systems/powertrains mainly based on fuel engines.
This also applies for forestry vehicle such as forwarders or harvesters which today typically are wheeled. The fact that most forestry vehicles are wheeled depends on that the opinion since the sixties was that these were felt to be more reliable than tracked vehicles. This has lately been started to be questioned as tracked vehicles e.g. facilitate lower impact on the ground, i.e. degradation of the ground.
In order to transfer the power from the fuel engine of a vehicle for creating drive torque of a wheel or track a large amount of gears, shafts, gear wheels, chain wheels or similar power transmitting components are typically needed which all need lubrication, maintenance and space. These components may also limit aspects such as e.g. ground clearance and how vehicle geometries may be constructed. Fuel engines also typically have a low efficiency.
These disadvantages results in vehicles of today including tracked vehicles being unsuitable for a number of different applications where there are demands on reliability in operation/environmental friendliness. This especially applies for tracked vehicles intended for forestry such as forwarders or harvesters which typically are operated day and night in multi-shifts and where losses of production caused by vehicle errors result in great financial consequences as the entire chain of logistics is affected. Today you go more and more towards so called “cut-to-length” logic within forestry which means that forwarders at the felling site cuts up timber based on information from clients regarding desired quantity, size and length. The timber is marked on the site and is then transported by a forwarder to a collection point where a timber vehicle such as a truck collects the timber and transports this further to the client such as a sawmill or a process industry. This combined with just-in-time logic results in a fall in production caused by error stand still of harvester or forwarder affecting all subsequent links in the logistics chain. Further the environment where these vehicles operate, i.e. felling sites and timber collecting sites, are located far away from service centres and/or service technicians which results in that it takes long time before service can be carried through by technicians on the site or in a workshop.
Consequently there is a need to present improvement within drive systems for tracked vehicles.
An object of the present invention is to provide a drive unit for a tracked vehicle which has low weight.
An additional object of the present invention is to provide a drive unit which is robust and has few moving parts.
An additional object of the present invention is to provide a drive unit for a tracked vehicle which is compact and takes up a small volume.
An additional object of the present invention is to provide a drive unit for a tracked vehicle which facilitates high operational reliability and efficiency for creating low operative expenses.
Another object of the present invention is to provide a drive unit for a tracked vehicle which facilitates service and maintenance.
An additional object of the present invention is to simplify service and maintenance of a in the tracked vehicle comprised track support beam and the components being parts thereof.